Recovery of software defined network from multiple failures: Openstate vs openflow

Software Defined Network (SDN) is an emerging network with clearer separation between control and data planes. Like non-SDN, SDN undergoes a recovery process upon occurrence of failures. The recovery process should take less than 50 msec to comply with service level agreement of Internet Service Providers (ISPs). Currently, it is possible for SDN to meet the requirement with Openstate standard or protocol. However, the results were based on single failures only. Multiple failures may also occur and unavoidable. In this research, formulae to estimate recovery times of Openflow and Openstate are derived and proposed. It is obvious from the formulae that Openstate recovery time is better or equivalent to Openflow. Thus, we also conducted experiments to analyze the performance of Openstate with multiple failures using Mininet simulation software, in terms of three metrics: communication overhead, computation overhead of controller and packet loss. The performance of Openstate is compared to Openflow to observe how much the former is better than the later. From the simulation results, we conclude that Openstate has faster recovery time than Openflow. On the average, recovery time is 70 msec and 85 msec for Openstate and Openflow, respectively. This indicates that Openstate should be improved for faster recovery time. © 2017 IEEE.